This invention is directed to nicotinamide-based compounds which act as inhibitors of JAK kinases. This invention is also directed to pharmaceutical compositions containing the nicotinamide compounds and methods of using the compounds or compositions to treat a condition mediated at least in part by JAK kinase activity. The invention is also directed to methods of making the compounds described herein.
Protein kinases constitute a large family of structurally related enzymes that are responsible for the control of a variety of signal transduction processes within cells (see, e.g., Hardie and Hanks, The Protein Kinase Facts Book, I and II, Academic Press, San Diego, Calif., 1995). Protein kinases are thought to have evolved from a common ancestral gene due to the conservation of their structure and catalytic function. Almost all kinases contain a similar 250-300 amino acid catalytic domain. The kinases can be categorized into families by the substrates they phosphorylate (e.g., protein-tyrosine, protein-serine/threonine, lipids, etc.). Sequence motifs have been identified that generally correspond to each of these families (see, e.g., Hanks & Hunter, (1995), FASEB J. 9:576-596; Knighton et al., (1991), Science 253:407-414; Hiles et al., (1992), Cell 70:419-429; Kunz et al., (1993), Cell 73:585-596; Garcia-Bustos et al., (1994), EMBO J. 13:2352-2361).
Many diseases are associated with abnormal cellular responses triggered by protein kinase-mediated events. These diseases include autoimmune diseases, inflammatory diseases, bone diseases, metabolic diseases, neurological and neurodegenerative diseases, cancer, cardiovascular diseases, allergies, asthma, alzheimer's disease and hormone-related diseases. As a consequence, there has been substantial efforts in medicinal chemistry to find inhibitors of protein kinases for use as therapeutic agents.
JAK kinases (Janus Kinases) are a family of cytoplasmic protein tyrosine kinases including JAK1, JAK2, JAK3 and TYK2. The JAKs play a crucial role in cytokine signaling. Each of the JAK kinases is selective for the receptors of certain cytokines, though multiple JAK kinases can be affected by particular cytokine or signaling pathways. Studies suggest that JAK3 associates with the common cytokine receptor gamma chain (Fcγ or γc) of the various cytokine receptors. JAK3 in particular selectively binds to receptors and is part of the cytokine signaling pathway for and activated by IL-2, IL-4, IL-7, IL-15 and IL-21. JAK1 interacts with, among others, the receptors for cytokines IL-2, IL-4, IL-7, IL-9 and IL-21, while JAK2 interacts with, among others, the receptors for IL-9 and TNF-α. Upon the binding of certain cytokines to their receptors (e.g., IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21), receptor oligomerization occurs, resulting in the cytoplasmic tails of associated JAK kinases being brought into proximity and facilitating the trans-phosphorylation of tyrosine residues on the JAK kinase. This trans-phosphorylation results in the activation of the JAK kinase.
The downstream substrates of JAK family kinases include the signal transducer activator of transcription (STAT) proteins. Phosphorylated JAK kinases bind various STAT (Signal Transducer and Activator of Transcription) proteins. STAT proteins, which are DNA binding proteins activated by phosphorylation of tyrosine residues, function both as signaling molecules and transcription factors and ultimately bind to specific DNA sequences present in the promoters of cytokine-responsive genes (Leonard et al., (2000), J. Allergy Clin. Immunol. 105:877-888).
JAK/STAT signaling has been implicated in the mediation of many abnormal immune responses such as allergies, asthma, autoimmune diseases such as transplant (allograft) rejection, rheumatoid arthritis, amyotrophic lateral sclerosis and multiple sclerosis, as well as in solid and hematologic malignancies such as leukemia and lymphomas. For a review of the pharmaceutical intervention of the JAK/STAT pathway see Frank, (1999), Mol. Med. 5:432:456 and Seidel et al., (2000), Oncogene 19:2645-2656.
Several mutated forms of JAK2 have been identified in a variety of disease settings, for example translocations resulting in the fusion of the JAK2 kinase domain with an oligomeriaztiondomain, TEL-JAK2, Bcr-JAK2 and PCM1-JAK2 have been implicated in the pathogenesis of various hematological malignancies (S D Turner and Alesander D R, Leukemia, 2006, 20, 572-582). Recently a unique mutation encoding a valine to phenylalanine substitution in JAK2 was detected in a significant number of myeloproliferative diseases such as polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis patients.
Constitutive activation of the STAT family, in particular STAT3 and STAT5 have been detected in a wide range of cancers and hyperproliferative diseases (Haura et al, Oncology, 2005, 2(6), 315-324). Further, aberrant activation of the JAK/STAT pathway provides an important proliferative and/or anti-apoptotic drive downstream of many kinases (e.g. Flt3, EGFR) whose constitutive activation have been implicated as key drivers in a variety of cancers and hyperproliferative disorders. Potent and specific inhibitors of JAK1 and JAK2 will be useful in the treatment of cancers including multiple myeloma, prostate, breast and lung cancer, B-cell Chronic Lymphocytic Leukemia, metastatic melanoma, multiple myeloma, and hepatoma.
JAK3 in particular has been implicated in a variety of biological processes. For example, the proliferation and survival of murine mast cells induced by IL-4 and IL-9 have been shown to be dependent on JAK3- and gamma chain-signaling (Suzuki et al., (2000), Blood 96:2172-2180). JAK3 also plays a crucial role in IgE receptor-mediated mast cell degranulation responses (Malaviya et al., (1999), Biochem. Biophys. Res. Commun. 257:807-813), and inhibition of JAK3 kinase has been shown to prevent type I hypersensitivity reactions, including anaphylaxis (Malaviya et al., (1999), J. Biol. Chem. 274:27028-27038). JAK3 inhibition has also been shown to result in immune suppression for allograft rejection (Kirken, (2001), Transpl. Proc. 33:3268-3270). JAK3 kinases have also been implicated in the mechanism involved in early and late stages of rheumatoid arthritis (Muller-Ladner et al., (2000), J. Immunal. 164:3894-3901); familial amyotrophic lateral sclerosis (Trieu et al., (2000), Biochem Biophys. Res. Commun. 267:22-25); leukemia (Sudbeck et al., (1999), Clin. Cancer Res. 5:1569-1582); mycosis fungoides, a form of T-cell lymphoma (Nielsen et al., (1997), Prac. Natl. Acad. Sci. USA 94:6764-6769); and abnormal cell growth (Yu et al., (1997), J. Immunol. 159:5206-5210; Catlett-Falcone et al., (1999), Immunity 10:105-115). Therefore, compounds that inhibit JAK-3 can be therapeutically useful in treatment of chronic and/or acute organ transplant and autoimmune diseases such as Type 1 diabetes, systemic lupus, multiple sclerosis, Crohn's disease and inflammatory diseases such as, asthma, psoriasis, chronic obstructive pulmonary disease.
JAK1, JAK2, and TYK2 are expressed ubiquitously, whereas JAK3 is expressed predominantly in hematopoietic cells. The JAK kinases, including JAK3, are abundantly expressed in primary leukemic cells from children with acute lymphoblastic leukemia, the most common form of childhood cancer, and studies have correlated STAT activation in certain cells with signals regulating apoptosis (Demoulin et al., (1996), Mol. Cell. Biol. 16:4710-6; Jurlander et al., (1997), Blood. 89:4146-52; Kaneko et al., (1997), Clin. Exp. Immun. 109:185-193; and Nakamura et al., (1996), J. Biol. Chem. 271: 19483-8). They are also known to be important for lymphocyte differentiation, function and survival. JAK-3 in particular plays an essential role in the function of lymphocytes, macrophages, and mast cells. Given the importance of this JAK kinase, compounds which modulate the JAK pathway, including those selective for JAK3, can be useful for treating diseases or conditions where the function of lymphocytes, macrophages, or mast cells is involved (Kudlacz et al., (2004) Am. J. Transplant 4:51-57; Changelian (2003) Science 302:875-878). Conditions in which targeting of the JAK pathway or modulation of the JAK kinases, particularly JAK3, are contemplated to be therapeutically useful include, leukemia, lymphoma, transplant rejection (e.g., pancreas islet transplant rejection, bone marrow transplant applications (e.g., graft-versus-host disease), autoimmune diseases (e.g., diabetes, rheumatoid arthritis, lupus, psoriasis), and inflammation (e.g., asthma, allergic reactions). Conditions which can benefit from JAK3 inhibition are discussed in greater detail below. Recent data on JAK inhibition has been reported in kidney allograft patients treated with CP-690,550 (Tasocitinib) and showed that markers of allogeneic response (interferon gamma) can be reduced (Van Gurp E A et al (2009) Transplantation 87:79-86).
In view of the numerous conditions that are contemplated to benefit by treatment involving modulation of the JAK pathway it is immediately apparent that new compounds that modulate JAK pathways and methods of using these compounds should provide substantial therapeutic benefits to a wide variety of patients. Provided herein are novel 2,4-nicotinamide-based compounds for use in the treatment of conditions in which targeting of the JAK pathway or inhibition of JAK kinases, particularly JAK3, are therapeutically useful.
Patents and patent applications related to modulation of the JAK pathway include: U.S. Pat. Nos. 5,728,536; 6,080,747; 6,080,748; 6,133,305; 6,177,433; 6,210,654; 6,313,130; 6,316,635; 6,433,018; 6,486,185; 6,506,763; 6,528,509; 6,593,357; 6,608,048; 6,610,688; 6,635,651; 6,677,368; 6,683,082; 6,696,448; 6,699,865; 6,777,417; 6,784,195; 6,825,190; 6,506,763; 6,784,195; 6,528,509; 6,608,048; 7,105,529; 6,699,865; 6,825,190; 6,815,439; 6,949,580; 7,056,944; 6,998,391; 7,074,793; 6,969,760; U.S. Pat. App. Pub. No. 2001/0007033 A1; 2002/0115173 A1; 2002/0137141 A1; 2003/0236244 A1; 2004/0102455 A1; 2004/0142404 A1; 2004/0147507 A1; and 2004/0214817 A1; and International patent applications WO 95/03701A1; WO 99/15500A1; WO 00/00202A1; WO 00/10981A1; WO 00/47583A1; WO 00/51587A2; WO 00/55159A2; WO 01/42246A2; WO 01/45641A2; WO 01/52892A2; WO 01/56993A2; WO 01/57022A2; WO 01/72758A1; WO 02/00661A1; WO 02/43735A1; WO 02/48336A2; WO 02/060492A1; WO 02/060927A1; WO 02/096909A1; WO 02/102800A1; WO 03/020698A2; WO 03/048162A1; WO 03/101989A1; WO 2004/016597A2; WO 2004/041789A1; WO 2004/041810A1; WO 2004/041814A1; WO 2004/046112A2; WO 2004/046120A2; WO 2004/047843A1; WO 2004/058749A1; WO 2004/058753A1; WO 2004/085388A2; WO 2004/092154A1; WO 2005/009957A1; WO 2005/016344A1; WO 2005/028475A2; and WO 2005/033107A1. Vertex has described aza indoles as JAK inhibitors (WO2005/95400). AstraZeneca has published quinoline 3-carboxamides as JAK 3 inhibitors (WO2002/92571) and other compounds for inhibition of all JAKs for the treatment of cancer (WO2008/135786).
While progress has been made in this field, there remains a need in the art for compounds that inhibit JAK kinases, as well as for methods for treating conditions in a patient, such as autoimmune diseases, inflammatory diseases, bone diseases, metabolic diseases, neurological and neurodegenerative diseases, cancer, cardiovascular diseases, allergies, asthma, alzheimer's disease and hormone-related diseases that can benefit from such inhibition. Moreover, the availability of compounds that selectively inhibit one of these kinases as compared to other kinases would also be desirable. The present invention satisfies this and other needs.